Prince William's marriage to fed-up wife Kate Middleton is in tatters after a heart-shattering miscarriage that claimed their twin girls! Kate stormed out of the couple’s country home, Anmer Hall — with the kids in tow — and moved back in with her parents, stunned palace sources reveal. William took off his wedding ring and left Britain in a huff for “an important animal conservation conference” in Vietnam!

Now the cracks in the royal union are being blown wide open, say insiders, as William and Kate reel from the tragedy of losing their unborn children. “Instead of consoling each other over the miscarriage,” a royal insider told The National ENQUIRER. “Wills and Kate started bickering — and things escalated to the point where a sobbing Kate walked out!”

The Duchess of Cambridge, already a mom of two, had tried to keep her pregnancy under wraps, but her devastating loss couldn't be kept a secret! “With all the issues Kate had when she was expecting her other children — Prince George and Princess Charlotte — she wanted to delay a public announcement,” said the source.

“Her worst nightmare happened when she suddenly fell ill. Although her doctor rushed to her side, the miscarriage couldn’t be prevented. Kate was shattered,” said the insider. Thrown into emotional turmoil, the heartbroken couple retreated to their country home in Norfolk. “But they couldn’t escape their problems,” said the source.

Speculation has been growing about the state of the five-year marriage, especially since they’ve been arguing over parenthood issues and Kate’s spending. William refuses to wear his wedding ring — and the duchess sparked divorce rumors when she shunned the wedding of her hubby’s best friend, Oliver Hicks, in early November.

“William and Kate have been relegated to junior royals now, and they blame each other for not stopping the takeover,” said the source. “William furiously pointed the finger at Kate squandering a staggering $1 million on a shop-til-you-drop spending spree. 'That just gave my father ammunition against us!'” he bellowed at a startled Kate.

And instead of commiserating over the miscarriage, the devious Duchess of Cornwall taunted Kate, revealed the insider. “'Suck it up and get back to work,' Camilla sneered. 'True royals don’t take time off. They put on a stiff upper lip and carry on, no matter what.'”

Added the source: “Camilla cruelly told Kate she should be spending time raising her two kids in the strict royal tradition instead of pampering them and 'turning them into spoiled brats!' That was the end for Kate! Furious and choking back tears, she screamed at William, ‘I’ve had enough!’ and walked out!”

After scooping up the kids, Kate went back to her parents’ $7 million estate in Bucklebury — some four hours away. “Her mother, Carole, comforted her and played peacemaker, persuading her to return home after a couple of days," the source said. “But there’s no doubt their fairytale marriage is in deep trouble!”